21684680366 has 32 divisors (see below), whose sum is σ = 33705745920. Its totient is φ = 10457004096.

The previous prime is 21684680359. The next prime is 21684680417. The reversal of 21684680366 is 66308648612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2564141 + ... + 2572583.

It is an arithmetic number, because the mean of its divisors is an integer number (1053304560).

Almost surely, 2^21684680366 is an apocalyptic number.

21684680366 is a deficient number, since it is larger than the sum of its proper divisors (12021065554).

21684680366 is a wasteful number, since it uses less digits than its factorization.

21684680366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8888.

The product of its (nonzero) digits is 1990656, while the sum is 50.

The spelling of 21684680366 in words is "twenty-one billion, six hundred eighty-four million, six hundred eighty thousand, three hundred sixty-six".